The transition from acute to chronic pain: might intensive care unit patients be at risk?

Post-Intensive Care Syndrome in Neurocritical Care Patients

Post-intensive care syndrome (PICS) refers to unintended consequences of critical care that manifest as new or worsening impairments in physical functioning, cognitive ability, or mental health. As intensive care unit (ICU) survival continues to improve, PICS is becoming increasingly recognized as a public health problem. Studies that focus on PICS have typically excluded patients with acute brain injuries and chronic neurodegenerative problems. However, patients who require neurocritical care undoubtedly suffer from impairments that overlap substantially with those encompassed by PICS. A major challenge is to distinguish between impairments related to brain injury and those that occur as a consequence of critical care. The general principles for the prevention and management of PICS and multidomain impairments in patients with moderate and severe neurological injuries are similar including the ICU liberation bundle, multidisciplinary team-based care throughout the continuum of care, and increasing awareness regarding the challenges of critical care survivorship among patients, families, and multidisciplinary team members. An extension of this concept, PICS-Family (PICS-F) refers to the mental health consequences of the intensive care experience for families and loved ones of ICU survivors. A dyadic approach to ICU survivorship with an emphasis on recognizing families and caregivers that may be at risk of developing PICS-F after neurocritical care illness can help improve outcomes for ICU survivors. In this review, we will summarize our current understanding of PICS and PICS-F, emerging literature on PICS in severe acute brain injury, strategies for preventing and treating PICS, and share our recommendations for future directions.

Characterization of Opioid Use in the Intensive Care Unit and Its Impact Across Care Transitions: A Prospective Study

Purpose: The objective of this study is to characterize opioid intensity in the intensive care unit (ICU) and its association with opioid utilization across care transitions. Methods: This is a prospective cohort study. Medically ill ICU patients with complete medication histories who survived to discharge were included. Opioid intensity was characterized based on IV morphine milligram equivalents (IV MME). Primary outcomes were opioid prescribing upon ICU and hospital discharge. Results: Opioids were prescribed to 34.1% and 31.1% of patients upon ICU and hospital discharge. Within the ≥50 mean IV MME/ICU day cohort, 64.7% of patients received opioids after ICU discharge compared to 45.8% and 13.6% in the 1-49 mean IV MME/ICU day and no opioid groups (P < .05). Within the ≥50 mean IV MME/ICU day cohort, 70.6% of patients were prescribed opioids after hospitalization compared to 37.3% and 13.6% of patients who received less or no opioids. (P < .05). Within the ≥50 mean IV MME/ICU day cohort, 29.4% of patients were opioid naïve and discharged with an opioid, which is over double compared to patients with lower opioid requirements (P < .05). Conclusion: Patients with higher mean daily ICU opioid requirements had increased opioid prescribing across care transitions despite preadmission opioid use.

Randomised controlled trial of analgesia for the management of acute severe pain from traumatic injury: study protocol for the paramedic analgesia comparing ketamine and morphine in trauma (PACKMaN)

BACKGROUND

Prehospital analgesia is often required after traumatic injury, currently morphine is the strongest parenteral analgesia routinely available for use by paramedics in the United Kingdom (UK) when treating patients with severe pain. This protocol describes a multi-centre, randomised, double blinded trial comparing the clinical and cost-effectiveness of ketamine and morphine for severe pain following acute traumatic injury.

METHODS

A two arm pragmatic, phase III trial working with two large NHS ambulance services, with an internal pilot. Participants will be randomised in equal numbers to either (1) morphine or (2) ketamine by IV/IO injection. We aim to recruit 446 participants over the age of 16 years old, with a self-reported pain score of 7 or above out of 10. Randomised participants will receive a maximum of 20 mg of morphine, or a maximum of 30 mg of ketamine, to manage their pain. The primary outcome will be the sum of pain intensity difference. Secondary outcomes measure the effectiveness of pain relief and overall patient experience from randomisation to arrival at hospital as well as monitoring the adverse events, resource use and cost-effectiveness outcomes.

DISCUSSION

The PACKMAN study is the first UK clinical trial addressing the clinical and cost-effectiveness of ketamine and morphine in treating acute severe pain from traumatic injury treated by NHS paramedics. The findings will inform future clinical practice and provide insights into the effectiveness of ketamine as a prehospital analgesia.

TRIAL REGISTRATION

ISRCTN, ISRCTN14124474. Registered 22 October 2020, https://www.isrctn.com/ISRCTN14124474.

Adverse Effects of Repeated, Intravenous Morphine on Recovery after Spinal Cord Injury in Young, Male Rats Are Blocked by a Kappa Opioid Receptor Antagonist

Immediately following spinal cord injury (SCI) patients experience pain associated with injury to the spinal cord and nerves as well as with accompanying peripheral injuries. This pain is usually treated with opioids, and most commonly with morphine. However, in a rodent model we have shown that, irrespective of the route of administration, morphine administered in the acute phase of SCI undermines long-term locomotor recovery. Our previous data suggest that activation of kappa opioid receptors (KORs) mediates these negative effects. Blocking KORs with norbinaltorphimine (norBNI), prior to a single dose of epidural morphine, prevented the morphine-induced attenuation of locomotor recovery. Because numerous cellular changes occur with chronic opioid administration compared with a single dose, the current study tested whether norBNI was also effective in a more clinically relevant paradigm of repeated, intravenous morphine administration after SCI. We hypothesized that blocking KOR activation during repeated, intravenous morphine administration would also protect recovery. Supporting this hypothesis, we found that blocking KOR activation in young, male rats prevented the negative effects of morphine on locomotor recovery, although neither norBNI nor morphine had an effect on long-term pain at the doses used. We also found that norBNI treatment blocked the adverse effects of morphine on lesion size. These data suggest that a KOR antagonist given in conjunction with morphine may provide a clinical strategy for effective analgesia without compromising locomotor recovery after SCI.

Morphine-induced changes in the function of microglia and macrophages after acute spinal cord injury

Background

Opioids are among the most effective and commonly prescribed analgesics for the treatment of acute pain after spinal cord injury (SCI). However, morphine administration in the early phase of SCI undermines locomotor recovery, increases cell death, and decreases overall health in a rodent contusion model. Based on our previous studies we hypothesize that morphine acts on classic opioid receptors to alter the immune response. Indeed, we found that a single dose of intrathecal morphine increases the expression of activated microglia and macrophages at the injury site. Whether similar effects of morphine would be seen with repeated intravenous administration, more closely simulating clinical treatment, is not known.

Methods

To address this, we used flow cytometry to examine changes in the temporal expression of microglia and macrophages after SCI and intravenous morphine. Next, we explored whether morphine changed the function of these cells through the engagement of cell-signaling pathways linked to neurotoxicity using Western blot analysis.

Results

Our flow cytometry studies showed that 3 consecutive days of morphine administration after an SCI significantly increased the number of microglia and macrophages around the lesion. Using Western blot analysis, we also found that repeated administration of morphine increases β-arrestin, ERK-1 and dynorphin (an endogenous kappa opioid receptor agonist) production by microglia and macrophages.

Conclusions

These results suggest that morphine administered immediately after an SCI changes the innate immune response by increasing the number of immune cells and altering neuropeptide synthesis by these cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-022-00739-3.

Pain assessment and analgesic management in patients admitted to intensive care: an Australian and New Zealand point prevalence study

Objective: To describe pain assessment and analgesic management practices in patients in intensive care units (ICUs) in Australia and New Zealand. Design, setting and participants: Prospective, observational, multicentre, single-day point prevalence study conducted in Australian and New Zealand ICUs. Observational data were recorded for all adult patients admitted to an ICU without a neurological, neurosurgical or postoperative cardiac diagnosis. Demographic characteristics and data on pain assessment and analgesic management for a 24-hour period were collected. Main outcome measures: Types of pain assessment tools used and frequency of their use, use of opioid analgesia, use of adjuvant analgesia, and differences in pain assessment and analgesic management between postoperative and non-operative patients. Results: From the 499 patients enrolled from 45 ICUs, pain assessment was performed at least every 4 hours in 56% of patients (277/499), most commonly with a numerical rating scale. Overall, 286 patients (57%) received an opioid on the study day. Of the 181 mechanically ventilated patients, 135 (75%) received an intravenous opioid, with the predominant opioid infusion being fentanyl. The median dose of opioid infusion for ventilated patients was 140 mg oral morphine equivalents. Of the 318 non-ventilated patients, 41 (13%) received patient-controlled analgesia and 76 (24%) received an oral opioid, with the predominant opioid being oxycodone. Paracetamol was administered to 63 ventilated patients (35%) and 164 non-ventilated patients (52%), while 2% of all patients (11/499) received a non-steroidal anti-inflammatory drug. Ketamine infusion and regional analgesia were used in 15 patients (3%) and 17 patients (3%), respectively. Antineuropathic agents (predominantly gabapentinoids) were used in 53 patients (11%). Conclusions: Although a majority of ICU patients were frequently assessed for pain with a validated pain assessment tool, cumulative daily doses of opioids were high, and the use of multimodal adjuvant analgesia was low. Our data on current pain assessment and analgesic management practices may inform further research in this area.

Depressive and Anxiety Symptoms in Severe COVID-19 Survivors: A Prospective Cohort Study

The coronavirus disease 2019 (COVID-19) has rapidly spread worldwide, leading to increased concerns about long-term patients' neuropsychiatric consequences. This study aims to describe the presence of depressive and anxiety symptoms in severe COVID-19 survivors and to identify associated baseline, in-hospital and post-discharge factors. This study is part of the MAPA longitudinal project conducted with severe COVID-19 patients admitted in Intensive Care Medicine Department (ICMD) of a University Hospital (CHUSJ) in Porto, Portugal. Patients with ICMD length of stay ≤ 24 h, terminal illness, major auditory loss or inability to communicate at follow-up assessment were excluded. All participants were assessed by telephone post-discharge (median = 101 days), with a comprehensive protocol assessing depressive and anxiety symptoms, cognition, Intensive Care Unit (ICU) memories recall and health-related quality of life. Out of a sample of 56 survivors (median age = 65; 68% males), 29% and 23% had depressive and anxiety symptoms, respectively. Depressive and anxiety symptoms were significantly more prevalent among younger survivors and were associated with cognitive complaints, emotional and delusions ICU memories and fear of having COVID-19 sequelae, sleep problems and pain after discharge (all p < 0.05). An important proportion of these survivors suffers from depression and anxiety symptoms post-discharge, namely younger ones and those who reported more cognitive complaints, ICU memories, fear of having COVID-19 sequelae, sleep problems and pain. These findings highlight the importance of psychological consequences assessment and planning of appropriate and multidisciplinary follow-up care after hospitalization due to COVID-19.

Pain, Anxiety, and the Continuous Use of Opioids and Benzodiazepines in Trauma Intensive Care Unit Survivors: An Exploratory Study

OBJECTIVE

To evaluate at-home opioid and benzodiazepine use, the degrees of pain and anxiety, and the incidence of probable withdrawal in post-discharge Trauma Intensive Care Unit (TICU) survivors.

METHODS

This was an exploratory study of post-TICU survivors who had participated in a previous study of opioid and benzodiazepine withdrawal. We surveyed survivors by telephone asking for retrospective information (during their first 4-months postdischarge- Time 1) and current information (around 2-years post-discharge- Time 2).

RESULTS

A mostly male (82%), young (median 38 years [IQR, 28-52]) sample of 27 TICU survivors reported using opioids (56%) at Time 1 for a median of 30 (IQR,14-90) days. Twelve percent of 26 survivors were still using opioids at Time 2. Sixty percent of the survivors had pain during Time 1, a median pain score of 6 (IQR, 5-8) on a 0-10 numeric rating scale (NRS).; 57% had pain at Time 2, median NRS score=6 (IQR, 4-7). Sixty-five percent of survivors had anxiety during Time 1, NRS median=7 (IQR, 5-9); 50% had anxiety at Time 2, NRS median= 6 (IQR, 3-7). At Time 1, 26% used prescribed benzodiazepines, and 12% used benzodiazepines at Time 2. Five and one of the 27 patients reported symptoms of opioid or benzodiazepine withdrawal, respectively, upon discontinuation or weaning.

CONCLUSION

Many TICU survivors had discontinued opioid/benzodiazepine prescriptions by 4-months post discharge while half reporting pain/anxiety for up to 2-years. Investigating the effects of acute-to-chronic pain in ICU survivors and gaining a better understanding of the mechanisms of prolonged opioid use are warranted.

The complications of opioid use during and post-intensive care admission: A narrative review

Opioids are a commonly administered analgesic medication in the intensive care unit, primarily to facilitate invasive mechanical ventilation. Consensus guidelines advocate for an opioid-first strategy for the management of acute pain in ventilated patients. As a result, these patients are potentially exposed to high opioid doses for prolonged periods, increasing the risk of adverse effects. Adverse effects relevant to these critically ill patients include delirium, intensive care unit-acquired infections, acute opioid tolerance, iatrogenic withdrawal syndrome, opioid-induced hyperalgesia, persistent opioid use, and chronic post-intensive care unit pain. Consequently, there is a challenge of optimising analgesia while minimising these adverse effects. This narrative review will discuss the characteristics of opioid use in the intensive care unit, outline the potential short-term and long-term adverse effects of opioid therapy in critically ill patients, and outline a multifaceted strategy for opioid minimisation.

Occurrence and characteristics of pain after ICU discharge: A longitudinal study

BACKGROUND

Pain is a serious problem for intensive care unit (ICU) patients, but we are lacking data on pain at the hospital ward after ICU discharge.

AIMS AND OBJECTIVES

To describe pain intensity, -interference with function and -location in patients up to 1 year after ICU discharge. To identify demographic and clinical variables and their association with worst pain intensity and pain interference.

DESIGN

A longitudinal descriptive secondary analysis of a randomized controlled trial on nurse-led follow-up consultations on post-traumatic stress and sense of coherence after ICU discharge.

METHODS

Pain intensity, -interference, and -location were measured using Brief Pain Inventory at the hospital ward and 3, 6, and 12 months after ICU discharge. For associations, data were analysed using multivariate linear mixed models for repeated measures.

RESULTS

Of 523 included patients, 68% reported worst pain intensity score above 0 (no pain) at the ward. Estimated means for worst pain intensity and -interference (from 0 to 10) after ICU discharge were 5.5 [CI 4.6-6.5] and 4.5 [CI 3.7-5.3], and decreased to 3.8 [CI 2.8-4.8] (P ≤ .001) and 2.9 [CI 2.1-3.7] after 12 months (P ≤ .001). Most common pain locations were abdomen (43%), lower lumbar back (28%), and shoulder/forearm (22%). At 12 months, post-traumatic stress (PTS) symptoms ≥25 (scale 10-70), female gender, shorter ICU stay, and more traumatic ICU memories were significantly associated with higher worst pain intensity. PTS symptoms ≥25, female gender, more traumatic ICU memories, younger age, and not having an internal medical diagnosis were significantly associated with higher pain interference.

CONCLUSIONS

Early after ICU discharge pain was present in 68% of patients. Thereafter, pain intensity and -interference declined, but pain intensity was still at a moderate level at 12 months. Health professionals should be aware of patients' pain and identify potentially vulnerable patients.

IMPLICATION FOR PRACTICE

Longitudinal assessment of factors associated with pain early after ICU discharge and the following year is a first step that could improve follow-up focus and contribute to reduced development of chronic pain.

Microglia: A Potential Therapeutic Target for Sepsis-Associated Encephalopathy and Sepsis-Associated Chronic Pain

Neurological dysfunction, one of the severe manifestations of sepsis in patients, is closely related to increased mortality and long-term complications in intensive care units, including sepsis-associated encephalopathy (SAE) and chronic pain. The underlying mechanisms of these sepsis-induced neurological dysfunctions are elusive. However, it has been well established that microglia, the dominant resident immune cell in the central nervous system, play essential roles in the initiation and development of SAE and chronic pain. Microglia can be activated by inflammatory mediators, adjacent cells and neurotransmitters in the acute phase of sepsis and then induce neuronal dysfunction in the brain. With the spotlight focused on the relationship between microglia and sepsis, a deeper understanding of microglia in SAE and chronic pain can be achieved. More importantly, clarifying the mechanisms of sepsis-associated signaling pathways in microglia would shed new light on treatment strategies for SAE and chronic pain.

Post-intensive care syndrome in a cohort of infants & young children receiving integrated care via a pediatric critical care & neurotrauma recovery program: A pilot investigation

OBJECTIVE

Children treated in the pediatric intensive care unit (PICU) often face difficulties with long-term morbidities associated with neurologic injuries and lifesaving PICU interventions termed Post-Intensive Care Syndrome (PICS). In an effort to identify and address critical issues related to PICS, we developed an integrated model of care whereby children and families participate in follow-up clinics with a neuropsychologist and a critical care physician. To demonstrate preliminary impact, we present pilot findings on the early identification and treatment of PICS in a cohort of infants and young children in our program through a combination of multi-professional direct assessment and parent proxy questionnaires.

METHOD

Thirty-three infants and children, ages 3-72 months, participated in our initial follow-up clinic where issues related to physical health/recovery, development/cognition, mood/behavior, and quality of life were screened 1-3 months after discharge from the PICU.

RESULTS

In comparison to pre-hospitalization functioning, direct assessment revealed new neurological concerns identified by the critical care physician in 33.3% of participants and new neurocognitive concerns identified by the neuropsychologist in 36.4% of participants. Caregiver reported measures showed significant issues with patient cognitive functioning, emotional functioning, sleep, and impact on the family. Participants and families experienced significant difficulties related to changes in functioning and disability. Parents/caregivers and clinicians demonstrated agreement on functioning across a variety of indicators; however, important divergence in assessments were also found highlighting the importance of multiple assessments and perspectives.

CONCLUSIONS

New PICS morbidities are common in the early phase of recovery after discharge in infants, young children and their families. Results demonstrate the benefits and need for timely PICU follow-up care that involves collaboration/integration of physicians, neuropsychologists, and families to identify and treat PICS issues.

CE: Managing Pain in Critically Ill Adults: A Holistic Approach

Nurses caring for critically ill adults are challenged to balance patient comfort with the risk of complications associated with analgesic therapy. Evidence gathered since 2013, when the Society of Critical Care Medicine (SCCM) published the Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the Intensive Care Unit, known as the PAD guidelines, gave rise to the SCCM 2018 publication of the Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU, known as the PADIS guidelines. This article discusses how the PADIS guidelines go beyond the PAD guidelines, providing specific guidance related to risk factors for pain, the assessment and management of pain in critical illness, and the ways in which the experience of pain in critical illness is intertwined with that of agitation, delirium, immobility, and sleep disruption. Tables summarize the key points in the PADIS guidelines, clarify the distinctions between PADIS and PAD, and describe the implications for nurses.

Persistent pain in intensive care survivors: a systematic review

BACKGROUND

According to earlier studies where the main aim has been quality of life, there is growing evidence of increased levels of persistent pain in survivors of critical illness. The cause of admission and several factors during intensive care may have associated risk factors for pain persistence. This systematic review aims to determine the incidence or prevalence of persistent pain after critical illness and to identify risk factors for it.

METHODS

Six databases were searched, and eventually nine studies were included in the final systematic process. The validity of observational and cross-sectional studies was analysed using the National Institute of Health 'Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies'.

RESULTS

The incidence of persistent pain after intensive care varied from 28% to 77%. Risk factors for persistent pain were acute pain at discharge from ICU, higher thoracic trauma score, surgery, pre-existing pain, organ failure, longer length of ventilator or hospital stay, and sepsis. No difference in incidence between medical and surgical patients was found.

CONCLUSIONS

New systematic, observational studies are warranted to identify persistent pain-related factors in intensive care to improve pain management protocols and thereby diminish the risk of persistent pain after ICU stay.

The first 24 h: opioid administration in people with spinal cord injury and neurologic recovery

STUDY DESIGN

Retrospective chart review.

OBJECTIVES

The objective of this study was to characterize opioid administration in people with acute SCI and examine the association between opioid dose and (1) changes in motor/functional scores from hospital to rehabilitation discharge, and (2) pain, depression, and quality of life (QOL) scores 1-year post injury.

SETTING

Spinal Cord Injury Model System (SCIMS) inpatient acute rehabilitation facility.

METHODS

Patients included in the SCIMS from 2008 to 2011 were linked to the National Trauma Registry and the electronic medical record. Three opioid dose groups (low, medium, and high) were defined based on the total morphine equivalence in milligrams at 24 h. The associations between opioid dose groups and functional/motor outcomes were assessed, as well as 1-year follow-up pain and QOL surveys.

RESULTS

In all, 85/180 patients had complete medication records. By 24 h, all patients had received opioids. Patients receiving higher amounts of opioids had higher pain scores 1 year later compared with medium- and low-dose groups (pain levels 5.5 vs. 4 vs. 1, respectively, p = 0.018). There was also an 8× greater risk of depression 1 year later in the high-dose group compared with the low-dose group (OR: 8.1, 95% CI: 1.2-53.7). In analyses of motor scores, we did not find a significant interaction between opioid dose and duration of injury.

CONCLUSIONS

These preliminary findings suggest that higher doses of opioids administered within 24 h of injury are associated with increased pain in the chronic phase of people with SCI.

Sedation strategies in children with pediatric acute respiratory distress syndrome (PARDS)

In this review, we discuss the changing landscape of sedation in mechanically ventilated children with pediatric acute respiratory distress syndrome (PARDS). While previous approaches advocated for early and deep sedation with benzodiazepines, emerging literature has highlighted the benefits of light sedation and use of non-benzodiazepine sedating agents, such as dexmedetomidine. Recent studies have emphasized the importance of monitoring multiple factors including, but not limited to, sedation depth, analgesia efficacy, opiate withdrawal, and development of delirium. Through this approach, we hope to improve PARDS outcomes. Overall, more research is needed to further our understanding of the best sedation strategies in children with PARDS.

Pain and Its Long-term Interference of Daily Life After Critical Illness

BACKGROUND

Persistent pain likely interferes with quality of life in survivors of critical illness, but data are limited on its prevalence and risk factors. We sought to determine the prevalence of persistent pain after critical illness and its interference with daily life. Additionally, we sought to determine if intensive care unit (ICU) opioid exposure is a risk factor for its development.

METHODS

In a cohort of adult medical and surgical ICU survivors, we used the brief pain inventory (BPI) to assess pain intensity and pain interference of daily life at 3 and 12 months after hospital discharge. We used proportional odds logistic regression with Bonferroni correction to evaluate the independent association of ICU opioid exposure with BPI scores, adjusting for potential confounders including age, preadmission opioid use, frailty, surgery, severity of illness, and durations of delirium and sepsis while in the ICU.

RESULTS

We obtained BPI outcomes in 295 patients overall. At 3 and 12 months, 77% and 74% of patients reported persistent pain symptoms, respectively. The median (interquartile range) pain intensity score was 3 (1, 5) at both 3 and 12 months. Pain interference with daily life was reported in 59% and 62% of patients at 3 and 12 months, respectively. The median overall pain interference score was 2 (0, 5) at both 3 and 12 months. ICU opioid exposure was not associated with increased pain intensity at 3 months (odds ratio [OR; 95% confidence interval], 2.12 [0.92-4.93]; P = .18) or 12 months (OR, 2.58 [1.26-5.29]; P = .04). ICU opioid exposure was not associated with increased pain interference of daily life at 3 months (OR, 1.48 [0.65-3.38]; P = .64) or 12 months (OR, 1.46 [0.72-2.96]; P = .58).

CONCLUSIONS

Persistent pain is prevalent after critical illness and frequently interferes with daily life. Increased ICU opioid exposure was not associated with worse pain symptoms. Further studies are needed to identify modifiable risk factors for persistent pain in the critically ill and the effects of ICU opioids on patients with and without chronic pain.

Chronic pain in critical care survivors: a narrative review

Chronic pain is an important problem after critical care admission. Estimates of the prevalence of chronic pain in the year after discharge range from 14% to 77% depending on the type of cohort, the tool used to measure pain, and the time point when pain was assessed. The majority of data available come from studies using health-related quality of life tools, although some have included pain-specific tools. Nociceptive, neuropathic, and nociplastic pain can occur in critical care survivors, but limited information about the aetiology, body site, and temporal trajectory of pain is currently available. Older age, pre-existing pain, and medical co-morbidity have been associated with pain after critical care admission. No trials were identified of interventions to target chronic pain in survivors specifically. Larger studies, using pain-specific tools, over an extended follow-up period are required to confirm the prevalence, identify risk factors, explore any association between acute and chronic pain in this setting, determine the underlying pathological mechanisms, and inform the development of future analgesic interventions.

Pain chronification: what should a non-pain medicine specialist know?

OBJECTIVE

Pain is one of the most common reasons for an individual to consult their primary care physician, with most chronic pain being treated in the primary care setting. However, many primary care physicians/non-pain medicine specialists lack enough awareness, education and skills to manage pain patients appropriately, and there is currently no clear, common consensus/formal definition of "pain chronification".

METHODS

This article, based on an international Change Pain Chronic Advisory Board meeting which was held in Wiesbaden, Germany, in October 2016, provides primary care physicians/non-pain medicine specialists with a narrative overview of pain chronification, including underlying physiological and psychosocial processes, predictive factors for pain chronification, a brief summary of preventive strategies, and the role of primary care physicians and non-pain medicine specialists in the holistic management of pain chronification.

RESULTS

Based on currently available evidence, we propose the following consensus-based definition of pain chronification which provides a common framework to raise awareness among non-pain medicine specialists: "Pain chronification describes the process of transient pain progressing into persistent pain; pain processing changes as a result of an imbalance between pain amplification and pain inhibition; genetic, environmental and biopsychosocial factors determine the risk, the degree, and time-course of chronification."

CONCLUSIONS

Early intervention plays an important role in preventing pain chronification and, as key influencers in the management of patients with acute pain, it is critical that primary care physicians are equipped with the necessary awareness, education and skills to manage pain patients appropriately.

Strategies for Acute and Critical Care Nurses Implementing Complementary Therapies Requested by Patients and Their Families

As consumer use of complementary and alternative medicine or modalities continues to increase in the United States, requests for these therapies in the acute and critical care setting will probably continue to expand in scope and frequency. Incorporation of complementary therapies in the plan of care is consistent with principles of patient- and family-centered care and collaborative decision-making and may provide a measure of relief for the distress of admission to an acute or critical care setting. An earlier article provided an overview of complementary and alternative therapies that nurses may encounter in their practices, with specific attention to implications for acute and critical care nurses. This article provides key information on the legal, ethical, safety, quality, and financial challenges that acute and critical care nurses should consider when implementing patient and family requests for complementary therapies.

Resilience in Survivors of Critical Illness in the Context of the Survivors' Experience and Recovery

RATIONALE

Post-intensive care syndrome (PICS), defined as new or worsening impairment in cognition, mental health, or physical function after critical illness, is an important development in survivors. Although studies to date have focused on the frequency of these impairments, fundamental questions remain unanswered regarding the survivor experience and the impact of the critical illness event on survivor resilience and recovery.

OBJECTIVES

To examine the association between resilience and neuropsychological and physical function and to contextualize these findings within the survivors' recovery experience.

METHODS

We conducted a mixed-methods pilot investigation of resilience among 43 survivors from two medical intensive care units (ICUs) within an academic health-care system. We interviewed survivors to identify barriers to and facilitators of recovery in the ICU, on the medical ward, and at home, using qualitative methods. We used a telephone battery of standardized tests to examine resilience, neuropsychological and physical function, and quality of life. We examined PICS in two ways. First, we identified how frequently survivors were impaired in one or more domains 6-12 months postdischarge. Second, we identified how frequently survivors reported that neuropsychological or physical function was worse.

MEASUREMENTS AND MAIN RESULTS

Resilience was low in 28% of survivors, normal in 63% of survivors, and high in 9% of survivors. Resilience was inversely correlated with self-reported executive dysfunction, symptoms of anxiety, depression, and post-traumatic stress disorder, difficulty with self-care, and pain (P < 0.05). PICS was present in 36 survivors (83.7%; 95% confidence interval, 69.3-93.2%), whereas 23 survivors (53.5%; 95% confidence interval, 37.6-68.8%) reported worsening of neuropsychological or physical function after critical illness. We identified challenges along the recovery path of ICU survivors, finding that physical limitations and functional dependence were the most frequent challenges experienced in the ICU, medical ward, and on return to home. Spiritual and family support facilitated recovery.

CONCLUSIONS

Resilience was inversely correlated with neuropsychological impairment, pain, and difficulty with self-care. PICS was present in most survivors of critical illness, and 54% reported neuropsychological or physical function to be worse, yet resilience was normal or high in most survivors. Survivors experienced many challenges during recovery, while spiritual and family support facilitated recovery.

Chronic intensive care-related pain: Exploratory analysis on predictors and influence on health-related quality of life

BACKGROUND

There is growing evidence for the development of chronic pain after intensive care. Nonetheless, there is only limited knowledge about factors leading to chronic intensive care-related pain (CIRP). Thus, the primary objective was the identification of predictors of CIRP. Moreover, we aimed to assess the impact of CIRP on patients' health-related quality of Life (HRQOL).

METHODS

Comprehensive information on patients' pain before ICU admission and present pain was collected longitudinally by means of the German Pain Questionnaire 6 and 12 months after ICU discharge (ICU_DC ). In addition, a subsample of patients underwent Quantitative Sensory Testing (QST). We used Generalized Estimating Equations to identify predictors of CIRP with logistic regression models.

RESULTS

In total, 204 patients (197/159 at 6/12 months after ICU_DC ) were available for the analyses. In the multivariate models, moderate to severe average pain in the 4 weeks after ICU_DC , lower age, female sex, increased inflammation and chronic pain conditions and increased levels of anxiety before ICU admission were predictive for CIRP. In addition, small fibre deficits and lower disease severity were associated with CIRP in the QST subsample (81 patients, 77/55 at 6/12 months after ICU_DC ). Patients with CIRP reported significantly lower HRQOL than patients without CIRP.

CONCLUSIONS

Chronic intensive care-related pain is associated with specific decrements in HRQOL. Knowledge about the identified predictors is of clinical and scientific importance and might help to reduce the incidence of CIRP.

SIGNIFICANCE

Chronic intensive care-related pain is associated with specific decrements in health-related quality of life. While most of the identified predictors for CIRP can only be considered as risk factors, especially adequate (post-) acute pain management should be studied as preventive strategy.

Patient Recollection of ICU Procedural Pain and Post ICU Burden: The Memory Study

OBJECTIVE

To assess patients' recollections of in-ICU procedural pain and its impact on post-ICU burden.

DESIGN

Prospective longitudinal study of patients who underwent ICU procedures.

SETTING

Thirty-four ICUs in France and Belgium.

PATIENTS

Two hundred thirty-six patients who had undergone ICU procedures.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Patients were interviewed 3-16 months after hospitalization about: 1) recall of procedural pain intensity and pain distress (on 0-10 numeric rating scale); 2) current pain; that is, having pain in the past week that was not present before hospitalization; and 3) presence of traumatic stress (Impact of Events Scale). For patients who could rate recalled procedural pain intensity (n = 56) and pain distress (n = 43), both were significantly higher than their median (interquartile range) in ICU procedural pain scores (pain intensity: 5 [4-7] vs 3 [2.5-5], p < 0.001; pain distress: 5 [2-6] vs 2 [0-6], p = 0.003, respectively.) Current pain was reported in 14% of patients. When comparing patients with and without current pain, patients with current pain recalled even greater ICU procedural pain intensity and pain distress scores than patients without current pain: pain intensity, 8 (6-8) versus 5 (3.25-7); p = 0.002 and pain distress, 7 (5-8) versus 4 (2-6); p = 0.01, respectively. Patients with current pain also had significantly higher Impact of Events Scale scores than those without current pain (8.5 [3.5-24] vs 2 [0-10]; p < 0.001).

CONCLUSION

Many patients remembered ICU, with far fewer able to rate procedure-associated pain. For those able to do so, recalled pain intensity and pain distress scores were significantly greater than reported in ICU. One in seven patients was having current pain, recalling even higher ICU procedural pain scores and greater traumatic stress when compared with patients without current pain. Studies are needed to assess the impact of ICU procedural pain on post-ICU pain recall, pain status over time, and the relationship between postdischarge pain status and post-ICU burden.

Peer Support as a Novel Strategy to Mitigate Post-Intensive Care Syndrome

Post-intensive care syndrome, a condition defined by new or worsening impairment in cognition, mental health, and physical function after critical illness, has emerged in the past decade as a common and life-altering consequence of critical illness. New strategies are urgently needed to mitigate the risk of neuropsychological and functional impairment common after critical illness and to prepare and support survivors on their road toward recovery. The present state of critical care survivorship is described, and postdischarge care delivery in the United States and the potential impact of the present-day fragmented model of care delivery are detailed. A novel strategy that uses peer support groups could more effectively meet the needs of survivors of critical illness and mitigate post-intensive care syndrome.

Monoclonal antibodies for chronic pain: a practical review of mechanisms and clinical applications

Context

Monoclonal antibodies are being investigated for chronic pain to overcome the shortcomings of current treatment options.

Objective

To provide a practical overview of monoclonal antibodies in clinical development for use in chronic pain conditions, with a focus on mechanisms of action and relevance to specific classes.

Methods

Qualitative review using a systematic strategy to search for randomized controlled trials, systematic and nonsystematic (narrative) reviews, observational studies, nonclinical studies, and case reports for inclusion. Studies were identified via relevant search terms using an electronic search of MEDLINE via PubMed (1990 to June 2017) in addition to hand-searching reference lists of retrieved systematic and nonsystematic reviews.

Results

Monoclonal antibodies targeting nerve growth factor, calcitonin gene-related peptide pathways, various ion channels, tumor necrosis factor-α, and epidermal growth factor receptor are in different stages of development. Mechanisms of action are dependent on specific signaling pathways, which commonly involve those related to peripheral neurogenic inflammation. In clinical studies, there has been a mixed response to different monoclonal antibodies in several chronic pain conditions, including migraine, neuropathic pain conditions (e.g., diabetic peripheral neuropathy), osteoarthritis, chronic back pain, ankylosing spondylitis, and cancer. Adverse events observed to date have generally been mild, although further studies are needed to ensure safety of monoclonal antibodies in early stages of development, especially where there is an overlap with non-pain-related pathways. High acquisition cost remains another treatment limitation.

Conclusion

Monoclonal antibodies for chronic pain have the potential to overcome the limitations of current treatment options, but strategies to ensure their appropriate use need to be determined.

Neurobiological Effects of Morphine after Spinal Cord Injury

Opioids and non-steroidal anti-inflammatory drugs are used commonly to manage pain in the early phase of spinal cord injury (SCI). Despite its analgesic efficacy, however, our studies suggest that intrathecal morphine undermines locomotor recovery and increases lesion size in a rodent model of SCI. Similarly, intravenous (IV) morphine attenuates locomotor recovery. The current study explores whether IV morphine also increases lesion size after a spinal contusion (T12) injury and quantifies the cell types that are affected by early opioid administration. Using an experimenter-administered escalating dose of IV morphine across the first seven days post-injury, we quantified the expression of neuron, astrocyte, and microglial markers at the injury site. SCI decreased NeuN expression relative to shams. In subjects with SCI treated with IV morphine, virtually no NeuN⁺ cells remained across the rostral-caudal extent of the lesion. Further, whereas SCI per se increased the expression of astrocyte and microglial markers (glial fibrillary acidic protein and OX-42, respectively), morphine treatment decreased the expression of these markers. These cellular changes were accompanied by attenuation of locomotor recovery (Basso, Beattie, Bresnahan scores), decreased weight gain, and the development of opioid-induced hyperalgesia (increased tactile reactivity) in morphine-treated subjects. These data suggest that morphine use is contraindicated in the acute phase of a spinal injury. Faced with a lifetime of intractable pain, however, simply removing any effective analgesic for the management of SCI pain is not an ideal option. Instead, these data underscore the critical need for further understanding of the molecular pathways engaged by conventional medications within the pathophysiological context of an injury.

Validation of the Danish version of the Critical Care Pain Observation Tool

BACKGROUND

Assessing pain in critically ill patients is a challenge even in an intensive care unit (ICU) with a no sedation protocol. The aim of this study was to validate the Danish version of the pain assessment method; Critical Care Pain Observation Tool (CPOT) in an ICU with a no sedation protocol.

METHODS

Seventy patients were included in this study. The patients were observed during a non-nociceptive procedure (wash of an arm) and a nociceptive procedure (turning). Patients were observed before, during, and 15 min after the two interventions (six assessments). Two observers participated in the data collection and CPOT scores were blinded to each other. Calculations of interrater reliability, criterion validity and discriminant validity were performed to validate the Danish version of CPOT.

RESULTS

The results indicated a good correlation between the two raters (all scores > 0.9 and P < 0.05). About 48 (68.6%) of the included patients were able to self-report pain. We found a significantly higher mean CPOT score at the nociceptive procedure than at rest or the non-nociceptive procedure (P < 0.05). No correlation was found between CPOT scores and physiological indicators. Patients self-reported pain and CPOT showed a significant correlation (P < 0.05). A CPOT score of ≥ 3 correlated with patients' self-reported pain (ROC AUC 0.83).

CONCLUSION

The Danish version of CPOT can be used to assess pain in critically ill patients, also when the ICU has a no sedation protocol. CPOT scores showed a good interrater reliability and correlates well with patient's self-reported pain.

Dependence of Nociceptive Detection Thresholds on Physiological Parameters and Capsaicin-Induced Neuroplasticity: A Computational Study

Physiological properties of peripheral and central nociceptive subsystems can be altered over time due to medical interventions. The effective change for the whole nociceptive system can be reflected in changes of psychophysical characteristics, e.g., detection thresholds. However, it is challenging to separate contributions of distinct altered mechanisms with measurements of thresholds only. Here, we aim to understand how these alterations affect Aδ-fiber-mediated nociceptive detection of electrocutaneous stimuli. First, with a neurophysiology-based model, we study the effects of single-model parameters on detection thresholds. Second, we derive an expression of model parameters determining the functional relationship between detection thresholds and the interpulse interval for double-pulse stimuli. Third, in a case study with topical capsaicin treatment, we translate neuroplasticity into plausible changes of model parameters. Model simulations qualitatively agree with changes in experimental detection thresholds. The simulations with individual forms of neuroplasticity confirm that nerve degeneration is the dominant mechanism for capsaicin-induced increases in detection thresholds. In addition, our study suggests that capsaicin-induced central plasticity may last at least 1 month.

Incidence and prognostic factors of chronic pain after isolated musculoskeletal extremity injury

BACKGROUND

Chronic pain in patients is usually related to an episode of pain following acute injury, emphasizing the need to prevent progression from acute to chronic pain. Multiple factors in the acute phase might be responsible for perpetuating the pain. The presentation of patients at the emergency department (ED) presents a prime opportunity to identify patients at high risk for chronic pain and to start appropriate treatment.

METHODS

The PROTACT study is a prospective follow-up study aiming to estimate the incidence and prognostic factors responsible for the development of chronic pain after musculoskeletal injury. Data including sociodemographic, pain, clinical, injury- or treatment-related and psychological factors of 435 patients were collected from registries and questionnaires at ED visit, 6-week, 3- and 6-month follow-up.

RESULTS

At 6 months post-injury, 43.9% of the patients had some degree of pain (Numeric Rating Scale (NRS) ≥1) and 10.1% had chronic pain (NRS ≥4). Patients aged over 40 years, in poor physical health, with pre-injury chronic pain, pain catastrophizing, high urgency level and severe pain at discharge were found to be at high risk for chronic pain.

CONCLUSIONS

Two prognostic factors, severe pain at discharge and pain catastrophizing, are potentially modifiable. The implementation of a pain protocol in the ED and the use of cognitive-behavioural techniques involving reducing catastrophizing might be useful.

A review of the literature on multiple factors involved in postoperative pain course and duration

OBJECTIVE

To review the literature on the progression from acute to chronic postoperative pain, to evaluate the evidence for the risk of progressing to persistent postoperative and chronic pain, and to identify characteristics of pharmacologic treatments to best tailor therapy to an individual patient's pain profile.

BACKGROUND

Pain is most commonly classified by duration (acute, chronic) and pathophysiology (nociceptive, neuropathic); however, these descriptors alone incompletely describe pain. Additionally, the transition between acute and chronic postoperative pain is not well understood.

METHODS

We conducted a qualitative review and evaluation of the literature on postoperative pain with respect to the above objectives.

RESULTS

Individualized pharmacologic treatments require a complete characterization of a patient's pain profile, in terms of frequency of pain over the course of a 24-hour day and over time thereafter, frequency and duration of pain flares, and presence of neuropathic pain. These considerations can help guide the choice of pharmacologic treatment to meet patient needs over a 24-hour day and over time after surgery. With respect to opioid analgesics, acute pain requires rapid onset of analgesia and the ability to titrate analgesia to the changing characteristics of pain over a short period. For these reasons, short-acting opioid analgesics have been preferred; however, there are opioid formulations with rapid onset and extended release for reduced dosing frequency. Although nociceptive pain can typically be controlled by titration of the dose of an opioid analgesic, neuropathic pain may respond better to the addition of an antineuropathic medication rather than to opioid dose escalation.

CONCLUSION

Advances in individualized pharmacologic treatment for postoperative pain have resulted in better pain control. Moreover, the recognition of sub-acute pain as a new entity is important because many surgical patients will need therapy beyond the first 8 days after surgery. In this group of patients the diagnosis of a neuropathic pain component will be important so that appropriate multimodal therapy may be implemented.

Small nerve fiber pathology in critical illness

BACKGROUND

Degeneration of intraepidermal nerve fibers (IENF) is a hallmark of small fiber neuropathy of different etiology, whose clinical picture is dominated by neuropathic pain. It is unknown if critical illness can affect IENF.

METHODS

We enrolled 14 adult neurocritical care patients with prolonged intensive care unit (ICU) stay and artificial ventilation (≥ 3 days), and no previous history or risk factors for neuromuscular disease. All patients underwent neurological examination including evaluation of consciousness, sensory functions, muscle strength, nerve conduction study and needle electromyography, autonomic dysfunction using the finger wrinkling test, and skin biopsy for quantification of IENF and sweat gland innervation density during ICU stay and at follow-up visit. Development of infection, sepsis and multiple organ failure was recorded throughout the ICU stay.

RESULTS

Of the 14 patients recruited, 13 (93%) had infections, sepsis or multiple organ failure. All had severe and non-length dependent loss of IENF. Sweat gland innervation was reduced in all except one patient. Of the 7 patients available for follow-up visit, three complained of diffuse sensory loss and burning pain, and another three showed clinical dysautonomia.

CONCLUSIONS

Small fiber pathology can develop in the acute phase of critical illness and may explain chronic sensory impairment and pain in neurocritical care survivors. Its impact on long term disability warrants further studies involving also non-neurologic critical care patients.

Chronic pain in survivors of critical illness: a retrospective analysis of incidence and risk factors

INTRODUCTION

Chronic pain has been reported in survivors of critical illness for many years after discharge from hospital. This study investigates the incidence and site of chronic pain in survivors of critical illness between 6 months and 1 year after hospitalization, including ICU admission. A retrospective analysis of the risk factors for chronic pain in this patient group was also completed.

METHODS

A questionnaire method was used to investigate the incidence of chronic pain and the specific body parts affected. A retrospective study and multivariable analysis were used to investigate the risk factors for chronic pain in this patient group. All survivors of a general intensive care unit (ICU) in South Wales in a 6-month period were included in this study.

RESULTS

Chronic pain was reported in 44% of all respondents. The shoulder was the most commonly reported joint affected by pain (22%). Risk factors for chronic pain between 6 months and 1 year after ICU discharge were increasing patient age and severe sepsis.

CONCLUSIONS

Chronic pain is a problem in survivors of critical illness, especially in the shoulder joint, and further studies are needed investigating therapeutic interventions that address this long-term problem.

The pain, agitation, and delirium practice guidelines for adult critically ill patients: a post-publication perspective

The recently published Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the Intensive Care Unit differ from earlier guidelines in the following ways: literature searches were performed in eight databases by a professional librarian; psychometric validation of assessment scales was considered in their recommendation; discrepancies in recommendation votes by guideline panel members are available in online supplements; and all recommendations were made exclusively on the basis of evidence available until December of 2010. Pain recognition and management remains challenging in the critically ill. Patient outcomes improve with routine pain assessment, use of co-analgesics and administration as well as dose adjustment of opiates to patient needs. Thoracic epidurals help ease patients undergoing abdominal aortic surgery. Little data exists to guide clinicians as to the type or dose of co-analgesics; no opiate choice is associated with better patient outcomes. Lighter or no sedation is beneficial, and interruption is desirable in patients who require deep sedation for specific pathologic states. Delirium screening is probably useful; no treatment modality can be unequivocally recommended, and the benefit of prophylaxis is established only for early mobilization. The details of these recommendations, as well as more recent publications that complement the guidelines, are provided in this commentary.